U.S. Pat. No. 6,214,402, describes a co-crystallization process between sugar and N-{N-(3,3-dimethylbutyl)-L-alpha-aspartyl}-L-phenylalanine I-methylester. This disclosure is addressed to a method for preparing co-crystallized sugar comprising the steps of mixing sugar with water with stifling, heating the mixture to 120° C., seeding the mixture with a pre-mixture comprising N-{N-(3,3-dimethylbutyl)-L-alpha-aspartyl}L-phenylalanine I-methylester and sugar, removing the mixture from heat and allowing it to cool along with vigorous stirring.
In connection with the state of the art documents, it is important to mention the existing differences. In said document U.S. Pat. No. 6,214,402 the sugar and neotame co-crystallization process was carried out under atmospheric pressure conditions, that is, at high temperatures, in this specific case at 120° C. In the case of the present disclosure, the product is obtained under vacuum pressure, 60 KPa-75 KPa, which corresponds to an operative temperature of 60° C.-75° C. In the latter case, the darkening of the mother liquor is significantly diminished, which darkening is promoted by high temperatures, which enhances the color of the final product.
On the other hand, in the co-crystallization process of sugar and neotame, the seeding is carried out with the mixture of sugar and neotame being in the oversaturation zone, thus producing a shock seeding, which generates a non-homogeneous crystal distribution at the end of the process. In the co-crystallization process of the present disclosure, the natural sweetener is fed after loading the batch foot in the equipment and this mixture is evaporated until saturation point is reached wherein an amount of powdered sugar and isopropyl alcohol suspension is added. The advantage of this methodology is that the added crystals in the seed, would be those that will be obtained at the end of the process having a homogeneous size and therefore having a lesser size variation coefficient.
Furthermore, no reference is made to separating the crystals of sugar juice or syrup in the patent for the sugar and neotame co-crystallization; a necessary operation for the obtention of a free-flowing granular product, that do not become compacted or compressed.
In the co-crystallization process of a preferred embodiment of the present disclosure, a starting liquor or syrup may have a brix of 55°, and may come from a white sugar melting, clearing, bleaching and filtering process, which generates a stock material having a better quality. U.S. Pat. No. 6,214,402, discloses a sugar and water mixture having 67° brix, with no previous treatment that improves or changes the characteristics of the solution.
Finally, the present disclosure uses natural sweeteners and, besides, there is the possibility of adding some other aggregate which gives a special characteristic to said product.
U.S. Pat. No. 4,362,757 describes a sugar crystallized product containing a heat sensitive substance, an acid substance or an inverted sugar. This crystallized sugar product is dry, granular, free flowing that does not become compact and is dispersible in water. The crystallized sugar products are formed in two steps: preparation of a sugar pre-mixture which is dry, granular or transformed with a heat sensitive substance, an inverted sugar or an acid, then it is crystallized through the concentration of the sugar syrup, adding a determined amount of pre-mixture and subjecting the mixture to impact.
The present disclosure has notable advantages over the U.S. Pat. No. 4,362,757, because in the latter the work is done at a high temperature between 124 and 149° C. (255 and 300° F.), which increases the solubility of sucrose in water, causing the oversaturation of 95-98% of solids. In the present disclosure, the maximum operative temperature is 75° C. and its saturation step is reached in a percentage of solids between 79-81%. The process conditions have a direct impact on the final product. The present disclosure radically improves the size distribution of the sugar crystal. The present disclosure decreases the effect of temperature on the color of the final sugar and on the sugar juice or syrup resulting from the centrifugation process. The present disclosure improves the homogeneity of the natural sweetener and the aggregate in this case, due to the fact that the crystallization is carried out under a controlled and regulated manner, thereby avoiding oversaturation that leads to the generation of new sucrose crystals that do not contain the sweetener or the aggregate. This control and regulation of the temperature is done through vacuum in the equipment and constant conditions of heat through water steam. In the mentioned US patent the oversaturation is controlled by removing the heat through water jackets or forced air flow, instead where the process can go out of control.